The present invention relates to devices for injecting, infusing, delivering, dispensing or administering substances, and to methods of making and using such devices. More particularly, the present invention relates to a device for administering a fluid product or substance which can be a medicine, a diagnostic agent or a cosmetic product. In some preferred embodiments, the invention is used in self-administering, although it is not limited to self-administration use, but can also be used in administering by medically trained staff.
In therapies in which persons who are not medically trained administer an active agent, for example to themselves, the administering devices used have to be simple but still reliable to handle. In particular, it is necessary to ensure that in devices which allow selecting or setting the product dosage to be administered the dosage set is displayed accurately, conveniently and unequivocally. In diabetes therapy—a preferred area of use for the present invention—it should also be taken into account that the persons administering the insulin to themselves may be visually impaired and that the dosage set should therefore be particularly clearly and unambiguously legible on a dosage scale or display. It is conducive to good legibility if the dosage scale is disposed on a display drum which can be moved rotationally and translationally, since in this case, the dosage scale can extend along and in the rotational direction of the display drum.
Devices of the type mentioned are known for example from WO 99/38554 A1. Typically, the devices are complex and require rotational blocks which allow a rotational movement by a piston rod in one rotational direction but prevent it in the other, and which additionally have to be adjusted to torques which are to be transferred or can only just still be transferred.
A very simple device of the type mentioned is known from WO 03/075985 A1. As with the devices of WO 99/38554, however, it requires two spindle drives which are both formed to not be self-locking, such that when only a small dosage is set, only a short stroke of the display drum is provided.